Empty? - Function Summary

Summary:

Returns TRUE if a series is at its tail.

Usage:

empty? series

Arguments:

series - The series argument. (must be: series port bitset)

Description:

This is a synonym for TAIL? The check is made relative to the current location in the series.

print empty? [] true

print empty? [1] false

The EMPTY? function is useful for all types of series. For instance, you can use it to check a string returned from the user:

str: ask "Enter name:" if empty? str [print "Name is required"] Enter name:

It is often used in conjunction with TRIM to remove black spaces from the ends of a string before checking it:

if empty? trim str [print "Name is required"]

Related:

found? - Returns TRUE if value is not NONE.
none? - Returns TRUE for none values.
tail? - Returns TRUE if a series is at its tail.